Electric switch



. Jan. 20, 1925; 1,523,664

l. E. SMITH ELECTRIC SWITCH Filed April 1'7. 1922 .2 Sheets-Sheet lK llli "Hl I mmmmm 1 Qmmmmm mmmmmmmm Ilm i INVENTOR. Ina EuS'mll/u BYATTORNEY.

Jan. 2 0, 1925.

1,523,664 l. E. sM|TH ELECTRIC SWITCH Filed April 1'7, 1922 2SheetsSheet 2 INVENTOR. fra E. Smc'ib 'BYQS ,BLW

A TTORNEY Patented Jan. 20, 1925.

UNITED STATES PATENT 'OFFICE ELECTRIC SWITCH.

Application filed April 17, 1922.

To all whom t may concern:

Be it known that I, IRA E. SMITH, a citizen of the United States,residing at Stockton, county of San Joaquin, State of California, haveinvented certain new and useful Improvements in Electric Switches; and Ido declare the following to be a full, clear, and exact description ofthe same, reference being had to the accompanying drawings, and to thecharacters of reference marked thereon, which form a part of thisapplication.

This invention relates to improvements in electric switches, andparticularly to a type of thermostatically or pressure operated switchto be used to control the generation of heat, steam, or other pressure.

The principal object of this invention is to provide a switch controlledas above stated, which is particularly7 adapted to be interposed in amotor circuit, the motor being in turn connected with a rheostat, andwhich is so arranged and constructed that until the heat or pressurearrives at a certain point, by means of the motor (which operates toproduce the heat or pressure) the circuit will be closed through theswitch to the motor direct, allowing the latter to run at full or normalspeed. Then the aforementioned heat or pressure point is passed, thecircuit direct to the motor will be broken, and the current instead willbe passed to the motor through the rheostat or other resistance slowingdown the motor; while at a still higher heat or pressure point thecircuit will bebroken entirely, stopping the motor, and will not againbe closed until the heat or pressure is reduced to the original point.

This switch is therefore adapted to be used not only with the abovementioned oil burning system to produce steam or hot air pressure, butwith air compressing and water pumping systems operated by electricmotors.

Another object is to provide an adjustment means on the switch toprovide for the cutting in of the rheostat, orthe breaking of thecircuit, with whatever degree of heat or pressure may be desired in anyparticular case.

Another object is to provide a positive acting switch which willfunction and be actuated with, but an extremely small amount of powerbeing necessary.

A further object of the invention'is to Serial No. 553,962.

produce a simple and inexpensive device and yet one which will beexceedingly eifective for the purposes for which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

ln the drawings similar characters of reference indicate correspondingparts in the several views.

Fig. l is a side view of my improved switch showing the same installedin connection with an ordinary form of steam or air pressure gage coil.

Fig. 2 is a front view of the switch detached, showing the same in itsnormal or at-rest position.

Fig. 3 is a similar view, showing one set of the contacts broken.

Fig. 4 is a similar sectional view, showing all the contacts broken.

Fig. 5 is an enlarged sectional view of a block showing a contact-pointconstruction.

Fig. 6 is a wiring diagram, showing my switch interposed in circuitwitha motor and rheostat.

Referring now more particularly to the characters of reference on thedrawings, the numeral l denotes a rigid and vertical back member,provided with top and bottom projections or flanges 2 and 3respectively. Slidable through metal bushings 2 set in said flanges is apin or stem 4 preferably having on its lower end a weight Between theflanges 2 and 3 are a pair of blocks 6 and 7, the upper one 6 beingfirmly but adjustably fixed to the stem 4, which passes therethrough,while the lower one 7, through which the stem also passes, isfrictionally but yieldably held to the stem by means of spring-pressedballs S or similar friction means mounted in said block, the pressure ofthe springs being adjustable, whereby the pressure of the balls againstthe stem may be varied.

The members l, 2, 3, 6 and 7 are preferably made of an insulatingmaterial, such as bakelite, which besides being a good insulator doesnot warp or change its shape with varying conditions of cold, heat andmoisture, and therefore the switch will work freely and well under anysuch conditions. The blocks 6 and 7 are normally spaced apart somewhatin order to allow for separablecontact points 9 and 10 being. placedbetween the'adjacent surfaces of the blocks 6 and 7 and for similarpointsll and 12 being placed: between the adjacent faces of the blocks 7and flange 3 respectively. Y

A binding post 13 is provided on the block 6 and connected to theContact 9, another post 14 on the block is connected in common. to thepoints 10 and 11, and still another :post: 15 on the flange 3 isconnected to the contact 12 thereof. Y

The Contact points 9, 10, 11 and 12 are preferably made of tungsten.metal with ab,- solutely flat contacting surfaces set in shortcap-screws A. which in Vturn are screwedV into threaded metal bushings Bconnected to the binding posts and are set and moulded in the flange 3and blocks Gand 7, This construction. makes repairs and replace? mentseasy and gives a solid, Well connected member. i y i Y Adjustablymounted in the upper flange 2 is a stop. pin 16, which projects freelythrough the block 6 but is adaptedV toA abutl against the block 7 whenthe latter is raised a predetermined distance. Y 4

The stem et is preferably notched or recessed as at 1f? soas to form a:definite seat for the Vadjustable spring pressed balls 8 so that blocksGand 7 are forced together and spring-locked,v when,y blocks Gand 7arein their lowvermost. position, in order to insure positive contactof. the points 9 and 10 when the blocks 6. and Tare. raising due to theexpansion of the pressure or thermostatic means.

The upper. end of the stem 4 above the switch is adjustably connected t0the. flexible coil or loop 18 of an ordinary pressure gage (see Fig. l)by meansof a lug 19 o n the free end of the coil.` through Which anadjustable screnv 2O freely passes. this screiv being threaded intoflexible jointed blocks 21 to which the stem et is-xed. The screwpreferably has a pin 22 projecting therethrough, and normally a certaindistance above the lug 19, so thatthe latter andthe cail may have acertain and predetermined amount of travel before any raising movementis imparted to thel stem and blocks, the flexibly jointed blockslpermitting movement oftheendof thev loop*l 18 not in adirect lineVvv'itlrthe stem t Without binding the latter.

The svvitch itself is fixed on a-rigid bracket 1c. To interpose theswitch in a circuit, a main line Wfiref23 leads to the post 13, a Wire24 leads from the post 14j through the rheostat or resistance 26 'to`the motor 27 through a Wire 28l beyond said resistance, WhilejanotherWire 25l leads from the post to a-eonnectionV with the'Wi-re '28 leadingdirectto the motor. The other lead 29 t0 thefmotor is connected to the`main line 30 in common With the Wire 23.

In operation, the stem andfblocks will be held inactive until thepressure in the mem- Vber 18 has expanded the same so that it current totra-veli through the Wires 23 and i 24, throughthe rheostat, slowing'down they motor. l I

This circuit Will remain closed until' the block 7 strikes against theadjustable'stop pinl, when with anyfurther u'pv'va'rd move ment of thecoiland stem,'th'eblock-TV is held from raising therewitlnthefballsbeing forced out of; their, recessed seat 17 in? the stem 4 and slippingonthelatteij.. and 'causing the-separating of the contacts 9,a r1;l-10,thus breaking the circuit com'pletelyi A Theswitch, and itsoperatingfmechanism, are preferably enclosedr in a'suitable hous-y ing,sol that they are; proteetedffromf'dirt and dampness, as, Well laspossible injury from othercauses. Y From the foregoing description itfwillbe readily seen that I have produced,- such a device assubstantially fulfills theobjeets1of the invention as s et forth.herein.

lVhile this specification sets, forth in, de-` tail the present andpreferredlr construction ofthe device. still. in practice suchdeviations from such detail'may be resorted toias do not form. adeparture fromj the spirit-of lthe invention, as defined. the .appendedclaims. v t

Having thus described. my invention, what I claim as new and.usefrilandf-desire to secure by Letters Patent is Y 1. An electricswitch comprising a,l pair of a-lined andmovable-blocks, a fixedflange/'beyond said blocks, contact points between saidA blocks` andbetweensaid flange andthe adj acent block, a stem having frictional.engagement kwith the latter block and! rigidly fixed to the other block,wherebyv said blocks will normally move together with. the movement ofthe stem, and means for causingthe Yseparation ofthe blocks after apredeterminedmovement ofthestem. Y

' 2. An 'electric switchcomprisingagpairof alined and movable blocks, -afixed flange-beyond saidbllocks, contact points between: said blocks andbetween said flange and the adjacentV block, a stemhavingV frictionalrengagement with the latter block and rigidly fixed tothe other block,whereby said blocks Will normally move together with the movement of thestem, and a stop pin 'mounted in the fixed member and adapted to abutagainst the frictionally engaged block after a predetermined movement ofsaid stem and blocks,

3. An electric switch comprising a fixed flange, a pair of independentblocks above said flange, contact points between said blocks and betweenthe flange and the adjacent block, a movable stem projecting through theblocks and fixed to the uppermost one thereof, means between the lowerblock and stem for causing yieldable engagement of said block and stem,and means for causing said engagement to yield and separate the blocksyafter a predetermined vertical movement has taken place.

al. An electric switch comprising a flange projecting therefrom, a pairof independent blocks above said flange, contact points between saidblocks and between the flange and the adjacent block, a movable stemprojecting through the blocks and fixed to the uppermost one thereof,means between the lower block and stem for causing yieldable engagementof said block and stem, and an adjustable and vertically disposed stoppin mounted to project into the path of movement of the lower blockafter a predetermined movement thereof with the stem.

5. An electric switch comprising a flange projecting therefrom, a pairof independent blocks above said flange, contact points between saidblocks and between the flange and the adjacent block, a movable stemprojecting through the blocks and fixed to the uppermost one thereof,spring pressed friction members in the lower block yieldably engagingthe stem whereby said blocks will move together with the stem, and meansfor holding the lower block from further movement while permitting thestem and upper block to move.

6. An electric switch comprising a flange projecting therefrom, a pairof independent blocks above said flange, contact points between saidblocls and between the flange and the adjacent block, a movable stemprojecting through the blocks and fixed to the uppermost one thereof,spring pressed friction members in the lower block yieldably engagingthe stem whereby said blocks will move together with the stem, and apressure gauge coil connected at its free end to the stem.

7. An electric switch including a back member, upper and lower flangesthereon, independent blocks positioned between said flanges, said back,flanges and blocks being of an insulation material, a stem slidablymounted in said flanges and connected to the blocks, and contact membersbetween the blocks and between one of said blocks and the adjacentflange.

8. An electric switch including a back member, flanges projectingtherefrom at both ends, independent blocks positioned between saidflanges, said back member blocks and flanges being of an insulationmaterial, meta-l bushings in said flanges, in alinement with each other,a stem slidably mounted through the bushings and blocks and connected tothe latter, and contact members between the blocks, and between one ofsaid blocks and the adjacent flange.

9. An electric switch including a fixed back member, a stem slidablymounted therewith, contact-bearing blocks connected to said stem, andexpanding loop connected at one end to a rigid pipe and at the other endto one end of the stem, and a rigid bracket mounted on the pipe andsupporting the back member of the switch.

10. An electric switch including a fixed back member, a stem slidablymounted therewith, contact-bearing blocks connected to said stem, anexpanding loop fixed at one end and free at the other, said latter endbeing adjacent the outer end of the stem, swivel jointed blocksconnected to that end of the stem, a lug on the adjacent end of the loopnormally resting on the outermost block, and an adjustable membersecured in said block and passing freely through the lug and adapted tobe engaged by the latter after a certain expansion of the loop has takenplace.

In testimony whereof I aflix my signature.

IRA EDWARD SMITH.

